UI: increase 3D view icon contrast over light colors

- Avoid using white with low alpha to make grey.
  Note that this is the second time we've run into this problem: T59626.

- Use a light backdrop when the icons are dark
  so they're visible over a black background.

1 files changed, 18 insertions, 4 deletions

diff --git a/source/blender/editors/space_view3d/view3d_gizmo_navigate.c b/source/blender/editors/space_view3d/view3d_gizmo_navigate.c
index a86e4ac7f98..cd1bdab9500 100644
--- a/source/blender/editors/space_view3d/view3d_gizmo_navigate.c
+++ b/source/blender/editors/space_view3d/view3d_gizmo_navigate.c
@@ -151,10 +151,24 @@ static void WIDGETGROUP_navigate_setup(const bContext *UNUSED(C), wmGizmoGroup *
 			gz->color_hi[3] = 0.1f;
 		}
 		else {
-			UI_GetThemeColorShade3fv(TH_HEADER, -40, gz->color);
-			UI_GetThemeColorShade3fv(TH_HEADER, 160, gz->color_hi);
-			gz->color[3] = 0.4f;
-			gz->color_hi[3] = 0.2f;
+			uchar icon_color[3];
+			UI_GetThemeColor3ubv(TH_TEXT, icon_color);
+			int color_tint, color_tint_hi;
+			if (icon_color[0] > 128) {
+				color_tint = -40;
+				color_tint_hi = 60;
+				gz->color[3] = 0.5f;
+				gz->color_hi[3] = 0.5f;
+			}
+			else {
+				color_tint = 60;
+				color_tint_hi = 60;
+				gz->color[3] = 0.5f;
+				gz->color_hi[3] = 0.75f;
+			}
+			UI_GetThemeColorShade3fv(TH_HEADER, color_tint, gz->color);
+			UI_GetThemeColorShade3fv(TH_HEADER, color_tint_hi, gz->color_hi);
+
 		}